fish : any of numerous cold-blooded strictly aquatic craniate vertebrates that include the bony fishes and usually the cartilaginous and jawless fishes and that have typically an elongated somewhat spindle-shaped body terminating in a broad caudal (see caudal 2) fin, limbs in the form of fins when present at all, and a 2-chambered heart by which blood is sent through thoracic gills to be oxygenated — Webster

Fish are the gill-bearing aquatic craniate animals that lack limbs with digits. They form a sister group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered paraphyletic by excluding the tetrapods (i.e., the amphibians, reptiles, birds and mammals which all descended from within the same ancestry). Because in this manner the term “fish” is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology. The traditional term pisces (also ichthyes) is considered a typological, but not a phylogenetic classification. — Wikipedia

Ichthyology, also known as fish science, is the branch of zoology devoted to the study of fish. This includes bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). While a large number of species have been discovered, approximately 250 new species are officially described by science each year. According to FishBase, 33,400 species of fish had been described by October 2016. — Wikipedia

Fish News -- ScienceDaily All about fish. Current research in marine biology including fish habitats, aquaculture, speciation, deep sea fish and more.

Researchers have projected significant changes in the habitat of commercially important American lobster and sea scallops on the Northeast U.S. continental shelf. They used a suite of models to estimate how species will react as waters warm. The researchers suggest that American lobster will move further offshore and sea scallops will shift to the north in the coming decades.

Researchers have used an unmanned aerial system (or drone) to gather data on schooling juvenile Atlantic bluefin tuna in the Gulf of Maine. This pilot study tested whether a drone could keep up with the tuna while also taking photographs that captured physical details of this fast-moving fish.

Mangrove trees -- valuable coastal ecosystems found in Florida and other warm climates - won't survive sea-level rise by 2050 if greenhouse gas emissions aren't reduced, according to a new study. Using sediment data from the last 10,000 years, an international team estimated the chances of mangrove survival based on rates of sea-level rise.

Warming ocean temperatures and acidification drastically reduce the skeletal strength and filter-feeding capacity of glass sponges, according to new research. The findings indicate that ongoing climate change could have serious, irreversible impacts on the sprawling glass sponge reefs of the Pacific Northwest and associated biodiversity -- the only known reefs of their kind in the world.

The Latin name for brook trout -- Salvelinus fontinalis -- means 'speckled fish of the fountains,' but a new study suggests, for the first time, that the larger streams and rivers those fountains, or headwaters, flow into may be just as important to the brook trout.

Researchers from North Carolina State University have found per- and polyfluoroalkyl substances (PFAS) in every step of the Yadkin-Pee Dee River food chain, even though the river does not have a known industrial input of these compounds. The study examined the entire aquatic ecosystem for PFAS compounds and identified strong links between ecosystem groups that lead to biomagnification, the process that leads to greater concentrations of these substances in animals that sit higher on the food […]

The contributions of researchers from The University of Texas at El Paso (UTEP) have yielded the first indication that carbon quantum dots, a class of nanoparticles, can be utilized to combat neurological disorders, according to a paper published in the journal Processes as part its special issue on protein biosynthesis and drug design and delivery.

Researchers have projected significant changes in the habitat of commercially important American lobster and sea scallops on the Northeast U.S. continental shelf. They used a suite of models to estimate how species will react as waters warm. The researchers suggest that American lobster will move further offshore and sea scallops will shift to the north in the coming decades.

The COVID-19 pandemic and resulting economic shutdowns have severely disrupted and spotlighted weaknesses in the U.S. food system. Farmers, food distributors and government agencies are working to reconfigure supply chains so that food can get to where it's needed. But there is a hidden, long-neglected dimension that should also be addressed as the nation rebuilds from the current crisis.